I'll have prep help the night before and am considering making the dumplings ahead, layering them on sheet pans and leaving them in the cooler overnight; then cooking the cooled noodles in the soup just before serving the next evening.

But, seriously.. When I was a banquet chef, I used to make up a huge batch of dumplings whenever I made it. I rolled it, cut it, and froze the rest for future use or for kitchen staff (used to eat them like pop corns). There was really no difference between the fresh ones and the frozen ones.

Your best bet is to try out before you do it, then you'd know for sure. If you are used to rolling it out and cutting it right away, then I can only imagine there is just little bit of texture difference because of the developed gluten and resting over night. But with those four ingredients, it should turn colors or anything like that after a night.